1. Field
The invention relates to a prosthesis for use by a person who has an amputation above the elbow.
2. State of the Art
Considerations concerning performance requirements of prosthetic apparatus are exceedingly complex. Various attempts have been made to provide operable prostheses. In conventional artificial arms, a mechanical system is employed with cables connected between the prosthesis and another part of the amputee's body. The amputee operates the prosthesis by pulling the cable by using drastic movements of the portion of the body to which the cables are attached. The movements required to pull the cable are large and unnatural.
The use of electrically driven prostheses has been attempted, and it has been suggested to use biological signals, such as myoelectric impulses from other muscles in the amputee, for control of the electrically driven prostheses. These developments, unfortunately, have not achieved any significant level of success. In many instances systems performed well in laboratory or other controlled environments, but could not withstand the rigors of continued daily use. Further, the electrically driven prostheses which have been devised heretobefore were overly complex, excessive in weight and unnatural in both function and appearance.
3. Objectives
A principal objective of the present invention is to provide a reliable prosthesis which is cosmetically appealing to amputees, is operated electrically to simulate as nearly as possible the elbow action of a natural arm, and is fitable and maintainable by prosthetists in the field. A particular objective of the invention is to provide a prosthesis which is formed of separate but interconnectable modules which can be quickly replaced by a replacement module in the field, with the defective module being transferred to a central facility adapted to rebuild the module. Another objective of the invention is to provide an arm prosthesis which is adapted to swing naturally as the wearer walks and which further moves to the command of the wearer in a natural motion. A still further objective of the invention is to provide an arm prosthesis having an electrically operated elbow locking mechanism which permits the wearer to lift loads that would otherwise exceed the capability of the elbow movement actuator and which also minimizes power consumption of the elbow actuator.